quad: add valgrind to CI

Problem

Memory leaks are bad. Memory leaks not caught are even worse.

Solution

Prevent the addition of any memory leaks at the application layer, by running valgrind on the virtual quad during the continuous integration tests.

merged

mentioned in commit afd0ebcd

This resolves https://git.ece.iastate.edu/danc/MicroCART_17-18/issues/15.

mentioned in issue #15 (closed)

mentioned in issue #11 (closed)